119. Pascal's Triangle II

Easy

Given an integer rowIndex, return the rowIndexth (0-indexed) row of the Pascal's triangle.

In Pascal's triangle, each number is the sum of the two numbers directly above it as shown:

Example 1:

Input: rowIndex = 3
Output:
 [1,3,3,1]

Example 2:

Input: rowIndex = 0
Output:
 [1]

Example 3:

Input: rowIndex = 1
Output:
 [1,1]

Constraints:

• 0 <= rowIndex <= 33

Follow up: Could you optimize your algorithm to use only O(rowIndex) extra space?

解題

Runtime: 0 ms, faster than 100%

Memory Usage: 2 MB, less than 87.6%

func getRow(rowIndex int) []int {
    ans := make([]int, 0)
    ans = append(ans, 1)

    for i:=1; i <= rowIndex; i++ {
        tmp := ans[i-1]
        tmp = tmp * (rowIndex + 1 - i)
        tmp = tmp /i
        ans = append(ans, tmp)
    }

    return ans
}